Very strange order

['Woger]

OK,

I had this morning an order, or to be more pecific two orders from one client within 1 minute. After that I got a confirmation from Ideal (dutch payment system) that a payment was done. I found out that both orders were paid together, but that only one order was put on "payment succesfull". It also said there was paid to much for the order.

Then it became even more strange. The customer got a discount of about 7.563% on both orders. The discount referred to a coupon which exists but doesn't have a voucher code. It just adds a €1,95 discount if you have items for more then €11,80 and an gift item which costs €1,95.

Now, on the first order there are products for €20 (but not the gift item) and a discount of €1,48. On the second order he orders the gift item twice but it is only €3,90 and there is a discount for €0,28.

 

I allready asked the customer how he did that, because I can't replicate it, but so far no answer. How can I debug this?

 

Greetings,

Roger